Photocurable composition, cured product of same, and coated article

Abstract

Provided is a photocurable composition comprising (A) surface-modified inorganic particles in which 1 to 30 parts by mass of at least one of an organosilicon compound represented by formula (1) and a hydrolysis product and a condensation product thereof is chemically bound to 100 parts by mass of inorganic particles and which have a median diameter of 1 to 60 nm in a volume-based particle size distribution, (B) a bifunctional (meth)acrylate, (C) a trifunctional (meth)acrylate and (D) a photoradical initiator, in which the blend amount of the component (A) is 10 to 35% by mass, and the total blend amount of the components (A), (B) and (C) is 70% by mass or more. (In the formula, R1 represents a hydrogen atom or the like; R2 represents an alkylene group; R3 represents an alkyl group or the like; R4 represents an alkoxy group or the like; and n represents an integer of 1 to 3.)

Description

Photocurable composition, cured product thereof, and coated article

[0001] The present invention relates to a photocurable composition, a cured product thereof, and a coated article, and more specifically to a photocurable composition which has low viscosity and gives a cured product exhibiting excellent abrasion resistance, a cured product thereof, and a coated article.

[0002] Photocurable coating compositions are widely used to coat transparent plastic materials because they have a short curing time and can be cured at low temperatures. Plastic materials have lower surface hardness than glass and are easily scratched. Therefore, photocurable coating films used in these applications require high transparency and abrasion resistance.

[0003] In addition, in recent years, from the viewpoints of protecting the natural environment and simplifying the manufacturing process, there has been a demand for the development of solvent-free photocurable coating compositions that do not require a solvent drying process and do not release volatile organic solvents into the atmosphere. However, for example, in order for a (meth)acrylic composition to exhibit excellent atmospheric curability and abrasion resistance of the cured film, it is necessary to incorporate a large amount of high-viscosity polyfunctional (meth)acrylic compounds, which results in a significant increase in viscosity of the coating composition. High-viscosity coatings are not suitable for coating methods such as spray coating and flow coating, which significantly limits the coating methods that can be used. Therefore, in recent years, there has been a demand for solvent-free photocurable coating compositions that combine low viscosity and excellent atmospheric curability and produce abrasion-resistant cured films.

[0004] Patent Documents 1 to 3 propose the addition of inorganic particles to a photocurable coating composition as a method for improving the abrasion resistance of a coating film, and report that inorganic particles whose surfaces have been treated with an organic compound in particular improve dispersibility in paints and the abrasion resistance of cured films. However, these photocurable coating compositions contain organic solvents, and in the absence of the solvent, they become highly viscous compositions.

[0005] Patent Documents 4 and 5 report solvent-free photocurable coating compositions containing surface-treated silica, but the use of silica makes the composition highly viscous and the resulting coating film has insufficient transparency.

[0006] Japanese Patent Application Laid-Open No. 2017-132975 Japanese Patent No. 6189547 Japanese Patent Application Laid-Open No. 2008-150484 Japanese Patent Application Laid-Open No. 2010-189620 Japanese Patent Application Laid-Open No. 2020-012078

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a substantially solvent-free, low-viscosity photocurable composition that gives a cured film that is both transparent and abrasion-resistant, a cured product thereof, and a coated article.

[0008] The present inventors have conducted extensive research to achieve the above-mentioned object, and have found that by blending surface-modified inorganic particles, the surfaces of which have been modified with an organosilicon compound having a specific (meth)acrylic group, a bifunctional (meth)acrylate, a trifunctional (meth)acrylate, and a photoradical initiator in specific proportions, a photocurable composition can be obtained that is substantially solvent-free yet has low viscosity and gives a cured film that combines transparency and abrasion resistance, thereby completing the present invention.In the present invention, the term "substantially" means that the solvent contained in the composition is less than 10% by mass.

[0009] That is, the present invention provides: 1. A photocurable composition comprising: (A) surface-modified inorganic particles having 1 to 30 parts by mass of at least one of an organosilicon compound represented by the following formula (1), a hydrolyzate thereof, and a condensate thereof chemically bonded to 100 parts by mass of inorganic particles, the particles having a median diameter of 1 to 60 nm in a volume-based particle size distribution; (B) a bifunctional (meth)acrylate; (C) a trifunctional (meth)acrylate; and (D) a photoradical initiator, wherein the blending amount of the component (A) is 10 to 35% by mass, and the combined blending amount of the components (A), (B), and (C) is 70% by mass or more; (In the formula, R 1 is a hydrogen atom or a methyl group, and R 2 is an alkylene group having 1 to 20 carbon atoms, and R 3 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R 4are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and n is an integer of 1 to 3. 2. The photocurable composition according to 1, wherein the inorganic particles are silica particles; 3. The photocurable composition according to 2, wherein the surface-modified inorganic particles have a D90 / D10 value of 3.2 or less in the volume-based particle size distribution; 4. The surface-modified inorganic particles are 29 The peak area (Q) from −105 to −130 ppm relative to the peak area (Q) from −80 to −130 ppm in the Si-NMR spectrum 4 ) ratio (Q 4 5. The photocurable composition according to any one of 2 or 3, wherein the sol-gel silica particles having a surface-modified ratio (R / Q) of 0.8 or less are further surface-modified with at least one compound selected from the group consisting of a silane compound represented by the following formula (5) and a disilazane compound represented by the following formula (6), R 5 3SiY (5) R 5 3Si-NH-SiR 5 3 (6) (wherein, R 5 are each independently an alkyl group having 1 to 8 carbon atoms, and each Y is independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 6 carbon atoms, an amino group, or a halogen atom. 6. A photocurable composition according to any one of 1 to 5, wherein the content of a volatile organic solvent relative to the entire composition is less than 10 mass %; 7. A photocurable composition having a kinematic viscosity at 25°C of 100 mm 2 / s or less; 8. a cured product obtained by curing the photocurable composition according to any one of 1 to 7; and 9. an article coated with the cured product according to 8.

[0010] According to the present invention, it is possible to obtain a solventless photocurable composition that has low viscosity and gives a cured product that has both excellent transparency and abrasion resistance. Therefore, the photocurable composition of the present invention can be applied to coating methods suitable for low viscosity coatings, such as spray coating and flow coating, and since it is substantially solvent-free, it is useful as a hard coat coating material with low environmental impact.

[0011] The present invention will be described in detail below. In the present invention, the term "(meth)acrylic group" means an "acrylic group" or a "methacrylic group."

[0012] [Photocurable Composition] The photocurable composition of the present invention contains the following components (A) to (D): (A) surface-modified inorganic particles, (B) a difunctional (meth)acrylate, (C) a trifunctional (meth)acrylate, and (D) a photoradical initiator.

[0013] <(A) Surface-Modified Inorganic Particles> Component (A) is a surface-modified inorganic particle having a median diameter of 1 to 60 nm in a volume-based particle size distribution, in which 1 to 30 parts by mass of at least one of an organosilicon compound represented by the following formula (1), its (partial) hydrolysate, and condensate is chemically bonded to 100 parts by mass of inorganic particles. The organosilicon compound represented by the following formula (1) is (partially) hydrolyzed to form a silanol compound, which is then used to treat inorganic particles and cause a dehydration condensation reaction with hydroxy groups on the surface of the inorganic particles, or the above compound is used without hydrolysis to cause a dealcoholization condensation reaction between alkoxy groups in the compound and hydroxy groups on the surface of the inorganic particles, thereby surface-modifying the inorganic particles, thereby improving the dispersibility of the inorganic particles in a photocurable composition.

[0014] (In the formula, R 1 is a hydrogen atom or a methyl group, and R 2 is an alkylene group having 1 to 20 carbon atoms, and R 3 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R 4 are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and n is an integer of 1 to 3.

[0015] (1) Inorganic Particles The elements constituting the inorganic particles used in the present invention are not particularly limited, and examples thereof include Group 13 elements, Group 14 elements (excluding carbon), first-series transition elements, second-series transition elements, third-series transition elements, lanthanides, etc. Particles of Group 13 elements are particularly suitable, including oxide particles derived from aluminum, boron, indium, etc. Particles of Group 14 elements (excluding carbon) are particularly suitable, including metal silicon particles and oxide particles derived from silicon, tin, etc. Particles of first-series transition elements are particularly suitable, including oxide particles derived from titanium, manganese, zinc, etc. These oxides are often used as light-absorbing materials of specific wavelengths. Particles of second-series transition elements are particularly suitable, including silver particles and oxide particles derived from yttrium, zirconium, etc. These oxides are often used as light-absorbing and fluorescent materials of specific wavelengths. Particles of third-series transition elements are particularly suitable, including gold particles and oxide particles derived from hafnium, tantalum, etc. As the lanthanoid particles, oxide particles derived from lanthanum, cerium, praseodymium, neodymium, terbium, dysprosium, ytterbium, etc. are suitable.

[0016] These metal oxides may be used singly or in combination of two or more. This "composite" has a broad meaning and includes both simple mixing and compounding via chemical bonds. Compounding via chemical bonds refers to a form represented by the following general formula (8): (M 1 O x ) d (M 2 O y ) e (8)

[0017] Here, M 1 is any one of the elements represented by the element symbols Al, B, In, Si, Ge, Sn, Ti, Mn, Zn, Y, Zr, Hf, Ta, La, Ce, Pr, Nd, Tb, Dy, and Yb. 2 is any one of Al, B, In, Si, Ge, Sn, Ti, Mn, Zn, Y, Zr, Hf, Ta, La, Ce, Pr, Nd, Tb, Dy, and Yb, and M1 x and y are elements that are not the same as those selected in M 1 If the valence of is a, then x = a / 2, M 2 If the valence of is b, then y can be expressed as y = b / 2. d and e are real numbers that satisfy d + e = 1, and also satisfy 0 < d < 1 and 0 < e < 1. That is, in the structure, M 1 and M 2 has a unit in which M is bonded via oxygen. 1 and M 2 may be scattered or unevenly distributed in the structure. 1 and M 2 The structure with M scattered throughout is seen in the co-hydrolyzates of multiple metal alkoxides. 1 and M 2 The structure in which is unevenly distributed is seen in core-shell type composite particles (particles having a metal oxide fine particle as a core and a shell of another metal oxide on the outside of this core), and is formed, for example, by hydrolyzing multiple types of metal alkoxides in a stepwise manner depending on the type.

[0018] The inorganic particles may be core-shell type composite fine particles having a core made of one or a composite of two or more of the above-mentioned metal elements or metal oxides, and a shell made of one or a composite of two or more of the above-mentioned metal element oxides on the outside of the core. Examples of such core-shell type composite fine particles include core-shell type composite fine particles having a core made of titanium oxide-tin oxide composite oxide (titanium oxide fine particles containing tin as a solid solution) and a shell made of silicon oxide on the outside of the core.

[0019] Specific examples of inorganic particles used in the present invention include particles of silica, aluminum oxide, titanium oxide, zinc oxide, cerium oxide, tin oxide, boron oxide, indium oxide, etc. When a dispersion of these particles is added to, for example, a coating paint, one or more types of inorganic particles are usually used depending on the purpose, so the dispersion of the present invention may contain multiple types of inorganic fine particles. Among the above inorganic particles, silica particles are preferred in terms of dispersibility in the composition and ease of availability.

[0020] When silica particles are used as inorganic particles, in the volume-based particle size distribution measured by dynamic light scattering, when the particle diameter at 10% by volume cumulative from the smallest particle diameter is defined as D10 and the particle diameter at 90% by volume cumulative from the smallest particle diameter is defined as D90, the value of D90 / D10 is not particularly limited, but is preferably 3.2 or less, more preferably 3 or less. The lower limit is not particularly limited, but is preferably 1 or more. A D90 / D10 of 3.2 or less indicates a narrow particle size distribution, and such a particle size distribution is preferable in that when added to a photocurable composition, it becomes easy to control the transparency and fluidity, and also has the advantage that highly regular particles are incorporated into the cured film, thereby improving the abrasion resistance and crack resistance of the cured film.

[0021] When silica particles are used as inorganic particles, the type of silica particles is not particularly limited, but wet silica produced by ion exchange or sol-gel method is preferred.In particular, sol-gel silica particles essentially composed of SiO2 units obtained by hydrolysis and condensation of tetrafunctional silane compounds and / or their (partial) hydrolysis condensation products are preferred.In addition, the sol-gel silica particles "essentially composed of SiO2 units" means that the particles are basically composed of SiO2 units, but are not composed only of these units, and have a large number of silanol groups at least on the surface as is commonly known.In addition, in some cases, it means that some of the hydrolyzable groups (hydrocarbyloxy groups) derived from the raw material tetrafunctional silane compounds and / or their partial hydrolysis condensation products may not be converted into silanol groups and may remain on the particle surface or inside.

[0022] Regarding silica particles, a method for distinguishing between sol-gel silica and ion-exchange silica is to determine the Q unit in the siloxane unit (Q represented by the following formula: 1 ~Q 4 Q in the entire tetrafunctional siloxane unit 4 It is effective to compare the ratio of units and the alkali metal components.

[0023] (In the formula, each X is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

[0024] In the present invention, the Q occupies the entire Q units of the siloxane. 4 The unit ratio is 29 It can be determined by Si-NMR measurement, specifically, the ratio of the peak area (Q) from −80 to −130 ppm to the peak area (Q) from −105 to −130 ppm 4 ) ratio (Q 4 The Q of the silica particles used in the present invention can be calculated as 4 / Q is usually preferably 0.8 or less, more preferably 0.2 to 0.8, and even more preferably 0.55 to 0.75. 4 When the ratio (R / Q) is 0.2 to 0.8, the abrasion resistance of the cured film is improved.

[0025] In the present invention, the peak area refers to the area (integral value) when signal intensity is plotted against chemical shift value (parts per million (ppm)). It is preferable to set a threshold for quadrature based on a specific standard S / N ratio. For example, the S / N ratio is preferably 5 or higher, more preferably 10 or higher, and even more preferably 20 or higher. An S / N ratio of less than 5 may be undesirable because it results in a thick baseline and poor integration accuracy. The integral may be determined by a computer-based Simpson method or the like, or by cutting a printed medium with a uniform planar density on which a spectrum is displayed into the spectral shape and measuring the mass.

[0026] 29 Although Si nuclear magnetic resonance spectroscopy can be performed in either a solid or a liquid, solid-state nuclear magnetic resonance spectroscopy requires the measurement sample to be dried as a pretreatment, and the results do not necessarily reflect the bonding state of silicon in the sample. Therefore, it is preferable to confirm by nuclear magnetic resonance spectroscopy in a liquid state. 29 The Si nucleus has a negative gyromagnetic ratio (γ B ), the nuclear Overhauser effect is reversed, suppressing the nuclear magnetic relaxation around the resonant nuclei. Therefore, measurement conditions that do not cause a significant negative nuclear Overhauser effect are preferred.

[0027] ​In the case of pulsed-Fourier transform nuclear magnetic resonance, this problem can be solved by using an appropriate pulse sequence. For example, it is preferable to use an off-resonance pulse sequence. 29 In Si nuclear magnetic resonance spectroscopy, it is preferable to use silicon-free materials for the sample tube and probe. Examples of materials that can be used for silicon-free nuclear magnetic resonance spectroscopy include polytetrafluoroethylene (Teflon (registered trademark)). Liquid 29 In Si nuclear magnetic resonance spectroscopy, an appropriate relaxation agent can be used to shorten the measurement time. Known reagents and the like (for example, Organometallics, 2008, Vol. 27, No. 4, pp. 500-502 and references therein) can be used as the relaxation agent. Chromium (III) acetylacetonate is particularly excellent because it has excellent solubility in organic solvents and does not cause the aggregation of titanium oxide. For example, chromium (III) acetylacetonate can be dissolved in deuterated chloroform (chloroform-d 3 ) to 1 mol dm -3 It is preferable to use a few drops of a solution dissolved at a concentration of about 1000 ppm as a relaxation agent, since this provides both relaxation effect and deuterium locking effect.

[0028] The notation for the resonance magnetic field is 29 The difference between the resonance field and the resonance field of the Si nucleus can be expressed in parts per million (ppm). According to this notation, the Q unit is −80 to −130 ppm, and the T unit (XSiO 3 / 2 (X is the same as above. The same applies below.)) is -30 to -80 ppm, D unit (X 2 SiO 2 / 2 ) is -10 to -30 ppm, M unit (X 3 SiO 1 / 2) can often be detected in the range of -10 to 15 ppm. Negative values ​​in the notation indicate that the resonance magnetic field differs from the reference line toward the higher magnetic field side. The width of the resonance line depends on the strength of the magnetic field of the nuclear magnetic resonance apparatus used for measurement, and the above-mentioned preferred resonance line range is, for example, the value when a magnetic field of 11.75 T (tesla) is applied. The magnetic field that can be used in the nuclear magnetic resonance apparatus is preferably 5 T or more and 20 T or less, more preferably 8 T or more and 15 T or less, and even more preferably 10 T or more and 13 T or less. When the magnetic field is less than 5 T, the S / N ratio becomes small, making measurement difficult, and when the magnetic field exceeds 20 T, the resonance apparatus becomes large and measurement may become difficult.

[0029] (2) Organosilicon Compound The organosilicon compound used in the present invention is represented by the following formula (1).

[0030] In the formula, R 1 is a hydrogen atom or a methyl group, and R 2 is an alkylene group having 1 to 20 carbon atoms, and R 3 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R 4 are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and n is an integer of 1 to 3.

[0031] In formula (1), R 2 The alkylene group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include methylene, ethylene, trimethylene, propylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and cyclohexylene groups. When the number of carbon atoms is large (8 or more), the fluidity and storage stability of the surface-modified inorganic particles become particularly good, and when the number of carbon atoms is small (3 or less), it is particularly effective in improving the abrasion resistance when introduced into a cured film.

[0032] R 3The alkyl group having 1 to 8 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, cyclopentyl, and cyclohexyl groups. Of these, those having 1 to 3 carbon atoms are preferred, and among these, methyl groups, which have little steric hindrance, are particularly preferred because they do not inhibit the reaction with the inorganic particle surfaces.

[0033] R 4 are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and examples of the halogen atom include a fluorine, chlorine, bromine, and iodine atom. 4 Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, etc. Among these, alkoxy groups are preferred, and in consideration of reactivity with the surface of inorganic particles, methoxy groups are particularly preferred.

[0034] n is an integer of 1 to 3, but in consideration of reactivity with the surface of inorganic particles, it is preferably 2 or 3, and more preferably 3. In addition, in formula (1), when n is 2 or 3, R 4 may be the same group or different groups.

[0035] Specific examples of the organosilicon compound represented by the formula (1) include, for example, (meth)acryloyloxymethyl methyl dimethoxysilane, (meth)acryloyloxymethyl trimethoxysilane, (meth)acryloyloxymethyl methyl diethoxysilane, (meth)acryloyloxymethyl triethoxysilane, (meth)acryloyloxymethyl trihydroxysilane, (meth)acryloyloxymethyl ethyl dimethoxysilane, (meth)acryloyloxymethyl propyl dimethoxysilane, 2-(meth)acryloyloxyethyl methyl dimethoxysilane, 2-(meth)acryloyloxyethyl trimethoxysilane, 2-(meth)acryloyloxyethyl methyl diethoxysilane, 2-(meth)acryloyloxyethyl triethoxysilane, 2-(meth)acryloyloxyethyl trihydroxysilane, 2-(meth)acryloyloxyethyl ethyl dimethoxysilane, 2-(meth)acryloyloxyethylpropyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropyltrihydroxysilane, 3-(meth)acryloyloxypropylethyldimethoxysilane, 3-(meth)acryloyloxypropylpropyldimethoxysilane, 4-(meth)acryloyloxybutylmethyldimethoxysilane, 4-(meth)acryloyloxybutyltrimethoxysilane, 4-(meth)acryloyloxybutylmethyldiethoxysilane, 4-(meth)acryloyloxybutyltriethoxysilane, 4-(meth)acryloyloxybutyltrihydroxysilane, 4-(meth)acryloyloxybutylethyldimethoxysilane, 4-(meth)acryloyloxybutylpropyldimethoxysilane, 5-(meth)acryloyloxypentylmethyldimethoxysilane, 5-(meth)acryloyloxypentyltrimethoxysilane, 5-(meth)acryloyloxypentylmethyldiethoxysilane,5-(meth)acryloyloxypentyltriethoxysilane, 5-(meth)acryloyloxypentyltrihydroxysilane, 5-(meth)acryloyloxypentylethyldimethoxysilane, 5-(meth)acryloyloxypentylpropyldimethoxysilane, 6-(meth)acryloyloxyhexylmethyldimethoxysilane, 6-(meth)acryloyloxyhexyltrimethoxysilane, 6-(meth)acryloyloxyhexylmethyldiethoxysilane, 6-(meth)acryloyloxyhexyltriethoxysilane, 6-(meth)acryloyloxyhexyltrihydroxysilane, 6-(meth)acryloyloxyhexylethyldimethoxysilane, 6-(meth)acryloyloxyhexylpropyldimethoxysilane, 7-(meth)acryloyloxyheptylmethyldimethoxysilane, 7-(meth)acryloyloxyheptyltrimethoxysilane, 7-(meth)acryloyloxyheptylmethyldiethoxysilane, 7-(meth)acryloyloxyheptyltriethoxysilane, 7-(meth)acryloyloxyheptyltrihydroxysilane, 7-(meth)acryloyloxyheptylethyldimethoxysilane, 7-(meth)acryloyloxyheptylpropyldimethoxysilane, 8-(meth)acryloyloxyoctylmethyldimethoxysilane, 8-(meth)acryloyloxyoctyltrimethoxysilane, 8-(meth)acryloyloxyoctylmethyldiethoxysilane, 8-(meth)acryloyloxyoctyltriethoxysilane, 8-(meth)acryloyloxyoctyltrihydroxysilane, 8-(meth)acryloyloxyoctylethyldimethoxysilane, 8-(meth)acryloyloxyoctylpropyldimethoxysilane, 9-(meth)acryloyloxynonylmethyldimethoxysilane, 9-(meth)acryloyloxynonyltrimethoxysilane, 9-(meth)acryloyloxynonylmethyldiethoxysilane, 9-(meth)acryloyloxynonyltriethoxysilane, 9-(meth)acryloyloxynonyltrihydroxysilane, 9-(meth)acryloyloxynonylethyldimethoxysilane, 9-(meth)acryloyloxynonylpropyldimethoxysilane,10-(meth)acryloyloxydecylmethyldimethoxysilane, 10-(meth)acryloyloxydecyltrimethoxysilane, 10-(meth)acryloyloxydecylmethyldiethoxysilane, 10-(meth)acryloyloxydecyltriethoxysilane, 10-(meth)acryloyloxydecyltrihydroxysilane, 10-(meth)acryloyloxydecylethyldimethoxysilane, 10-(meth)acryloyloxydecylpropyldimethoxysilane, 11-(meth)acryloyloxyundecylmethyldimethoxysilane, 11-(meth)acryloyloxyundecyltrimethoxysilane, 11-(meth)acryloyloxyundecylmethyldiethoxysilane, 11-(meth)acryloyloxyundecyltriethoxysilane, 11-(meth)acryloyloxyundecyltrihydroxysilane, 11-(meth)acryloyloxyundecylethyldimethoxysilane, 11-(meth)acryloyloxyundecylpropyldimethoxysilane, 12-(meth)acryloyloxydodecylmethyldimethoxysilane, 12-(meth)acryloyloxydodecyltrimethoxysilane, 12-(meth)acryloyloxydodecylmethyldiethoxysilane, 12-(meth)acryloyloxydodecyltriethoxysilane, 12-(meth)acryloyloxydodecyltrihydroxysilane, 12-(meth)acryloyloxydodecylethyldimethoxysilane, 12-(meth)acryloyloxydodecylpropyldimethoxysilane, 13-(meth)acryloyloxytridecylmethyldimethoxysilane, 13-(meth)acryloyloxytridecyltrimethoxysilane, 13-(meth)acryloyloxytridecylmethyldiethoxysilane, 13-(meth)acryloyloxytridecyltriethoxysilane, 13-(meth)acryloyloxytridecyltrihydroxysilane, 13-(meth)acryloyloxytridecylethyldimethoxysilane, 13-(meth)acryloyloxytridecylpropyldimethoxysilane, 14-(meth)acryloyloxytetradecylmethyldimethoxysilane, 14-(meth)acryloyloxytetradecyltrimethoxysilane,Examples thereof include 14-(meth)acryloyloxytetradecylmethyldiethoxysilane, 14-(meth)acryloyloxytetradecyltriethoxysilane, 14-(meth)acryloyloxytetradecyltrihydroxysilane, 14-(meth)acryloyloxytetradecylethyldimethoxysilane, 14-(meth)acryloyloxytetradecylpropyldimethoxysilane, etc. These may be used alone or in combination of two or more.

[0036] Among these, the compounds represented by the following formulas (2) to (4) are particularly preferred. (In the formula, R 1 , R 3 , R 4 and n is the same as above.

[0037] In particular, from the viewpoints of improving the abrasion resistance of the coating film and being readily available, 3-(meth)acryloyloxypropyltrimethoxysilane, 8-(meth)acryloyloxyoctyltrimethoxysilane, and (meth)acryloyloxymethyltrimethoxysilane are preferred.

[0038] The amount of the organosilicon compound represented by the above formula (1) used is 1 to 30 parts by mass, and preferably 10 to 20 parts by mass, per 100 parts by mass of the inorganic particles, from the viewpoints of improving abrasion resistance by increasing the crosslink density, dispersibility in the photocurable composition, and improving flowability.

[0039] (3) Other Silane Compounds The surface-modified inorganic particles of the component (A) may be further surface-modified with one or more silane compounds represented by the following formula (5) and / or the following formula (6): R 5 3SiY (5) R 5 3Si-NH-SiR 5 3 (6)

[0040] In the above formula (5), R 5 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms, and more preferably 1 or 2 carbon atoms. 5The monovalent hydrocarbon group represented by R may be linear, branched, or cyclic, and examples thereof include alkyl groups, alkenyl groups, aryl groups, and aralkyl groups. 5 Specific examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, and n-butyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as 2-phenylethyl and 2-phenylpropyl. Of these, alkyl groups such as methyl, ethyl, and n-propyl are preferred, and methyl and ethyl are particularly preferred. Some or all of the hydrogen atoms in these monovalent hydrocarbon groups may be substituted with halogen atoms such as fluorine, chlorine, and bromine, preferably fluorine atoms.

[0041] Y is a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an amino group, an acyloxy group, or a halogen atom. Examples of the alkoxy group include methoxy, ethoxy, and n-propoxy groups. Examples of the amino group include N,N-dimethylamino and N,N-diethylamino groups. Examples of the acyloxy group include acetoxy groups. Examples of the halogen atom include those similar to those described above. Among these, a hydroxyl group and a methoxy group are preferred.

[0042] Specific examples of the compound represented by formula (5) include monosilanol compounds such as trimethylsilanol and triethylsilanol; monochlorosilanes such as trimethylchlorosilane and triethylchlorosilane; monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane; monoaminosilanes such as trimethylsilyldimethylamine and trimethylsilyldiethylamine; and monoacyloxysilanes such as trimethylacetoxysilane. These may be used alone or in combination of two or more. Among these, preferred are trimethylsilanol, trimethylmethoxysilane, and trimethylsilyldiethylamine, and particularly preferred are trimethylsilanol and trimethylmethoxysilane.

[0043] Specific examples of the compound represented by formula (6) include hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane, hexa(n-butyl)disilazane, hexa(i-butyl)disilazane, hexa(t-butyl)disilazane, hexapentyldisilazane, hexahexyldisilazane, hexaheptyldisilazane, hexaoctyldisilazane, and hexa(2-ethylhexyl)disilazane. These may be used alone or in combination of two or more. Of these, hexamethyldisilazane is preferred.

[0044] When the compound represented by formula (5) and / or formula (6) is used, the amount used is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass, and particularly preferably 8 to 12 parts by mass, relative to 100 parts by mass of the inorganic particles. When the amount used is 20 parts by mass or less, the amount of unreacted silane compound remaining can be suppressed, and the abrasion resistance of the cured product is improved, which is preferable, and when the amount used is 1 part by mass or more, the storage stability of the inorganic particle dispersion is improved, which is preferable.

[0045] The surface-modified inorganic particles of component (A) have a median diameter (D50), which is the particle diameter at a cumulative 50% by volume in a volume-based particle size distribution, of 1 to 60 nm, preferably 5 to 40 nm, and more preferably 10 to 30 nm. If D50 is less than 1 nm, the abrasion resistance of the cured film will be poor, and if D50 exceeds 60 nm, the transparency of the cured film will be impaired. The median diameter can be measured by dynamic light scattering using a laser beam with an apparatus such as a Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.).

[0046] Furthermore, in the volume-based particle size distribution of the surface-modified inorganic particles as measured by dynamic light scattering, the value of D90 / D10 is not particularly limited, but is preferably 3.2 or less, and more preferably 3 or less. The lower limit is not particularly limited, but is preferably 1 or more.

[0047] The blending amount of component (A) in the photocurable composition is 10 to 35% by mass, and preferably 20 to 30% by mass. If the content of the surface-modified inorganic particles is less than 10% by mass, the photocurability and abrasion resistance will be insufficient, and if it exceeds 35% by mass, the viscosity of the composition will be too high.

[0048] The component (A) may be added to the photocurable composition of the present invention in the form of a powder. However, it is preferable to prepare a dispersion in advance using a bifunctional (meth)acrylate of the component (B) and / or a trifunctional (meth)acrylate of the component (C) as a dispersion medium, and then mix the dispersion into the composition, since this makes it possible to prevent particle aggregation while reducing the amount of volatile organic solvent used.

[0049] (4) Method for Producing Surface-Modified Inorganic Particles Next, an example of a method for producing surface-modified inorganic particles of the present invention will be described in detail. The component (A) used in the present invention is a surface-modified inorganic particle obtained by surface-treating inorganic particles. When silica particles are used as the inorganic particles, they can be produced, for example, by a method including the following steps (α), (β), and, if necessary, (γ): Step (α): A step of synthesizing sol-gel silica particles; Step (β): A step of surface-treating the sol-gel silica with an organosilicon compound; Step (γ): A step of replacing the dispersion medium;

[0050] Each step will be explained below. Step (α): Step of synthesizing sol-gel silica particles Step (α) is a step of obtaining an organic solvent / water dispersion of hydrophilic sol-gel silica particles by hydrolyzing and condensing at least one of a silane compound represented by the following formula (7), its (partial) hydrolysate, and its condensate in a mixed solvent of a hydrophilic organic solvent and water in the presence of a basic substance. Si(OR 6 ) 4 (7)

[0051] In the above formula (7), R 6 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. 6 As the monovalent hydrocarbon group, R 5Among the groups exemplified in 1, the same groups having 1 to 6 carbon atoms can be mentioned, but preferably those having 1 to 4 carbon atoms, more preferably alkyl groups such as methyl, ethyl, n-propyl, and n-butyl groups, and particularly preferably methyl and ethyl groups.

[0052] Specific examples of the silane compound represented by formula (7) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetra-n-butoxysilane; and tetraaryloxysilanes such as tetraphenoxysilane. Among these, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetra-n-butoxysilane are preferred, and tetramethoxysilane and tetraethoxysilane are particularly preferred. Furthermore, examples of hydrolysis condensates of these compounds include methyl silicate and ethyl silicate.

[0053] The hydrophilic organic solvent used to hydrolyze and condense the silane compound is not particularly limited as long as it dissolves at least one of the silane compound represented by formula (7) above, its (partial) hydrolysate, and condensate, and water. Examples include alcohols such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and cellosolve acetate; ketones such as acetone and methyl ethyl ketone; and ethers such as dioxane and tetrahydrofuran. Among these, alcohols and cellosolves are preferred, alcohols are more preferred, and methanol and ethanol are particularly preferred. As the number of carbon atoms in the alcohol increases, the particle size of the resulting spherical silica particles increases. Therefore, methanol is preferred for obtaining the desired small-diameter silica particles.

[0054] Specific examples of the basic substance include ammonia, dimethylamine, diethylamine, etc., preferably ammonia and diethylamine, and particularly preferably ammonia. These basic substances may be dissolved in a required amount in water, and the resulting aqueous solution (basic) may then be mixed with the hydrophilic organic solvent.

[0055] The amount of water used in step (α) is preferably 0.5 to 5 mol, more preferably 0.6 to 3 mol, and particularly preferably 0.7 to 2 mol, per 1 mol of the total hydrocarbyloxy groups of the silane compound represented by formula (7) and its (partial) hydrolysate and condensate. The ratio of the hydrophilic organic solvent to water is preferably 0.5 to 10, more preferably 2 to 9, and particularly preferably 3 to 8, by mass. In this case, the larger the amount of the hydrophilic organic solvent, the smaller the silica particle size.

[0056] The amount of the basic substance is preferably 0.01 to 2 mol, more preferably 0.02 to 0.5 mol, and particularly preferably 0.04 to 0.12 mol, per 1 mol of the total of at least one hydrocarbyloxy group in the tetrafunctional silane compound represented by general formula (7) and its (partial) hydrolysate and condensate. In this case, the smaller the amount of the basic substance, the smaller the silica particle size.

[0057] The hydrolysis and condensation of the silane compound represented by formula (7) can be carried out by a known method, for example, by adding the silane compound to a mixture of water and a hydrophilic organic solvent containing a basic substance. After adding the silane compound represented by formula (7), the reaction is preferably carried out at a reaction temperature of 20 to 120°C for a reaction time of 1 to 8 hours, more preferably at a reaction temperature of 20 to 100°C for a reaction time of 1 to 6 hours.

[0058] The concentration of the sol-gel silica particles in the organic solvent / water dispersion in step (α) is preferably 5 to 30% by mass, more preferably 10 to 25% by mass.

[0059] Step (β): Silica Surface Treatment Step This step is a step of treating the surfaces of the hydrophilic spherical silica particles by adding at least one of an organosilicon compound represented by the following formula (1), and its (partial) hydrolysate and condensate to the dispersion of hydrophilic sol-gel silica particles obtained in step (α).

[0060] (In the formula, R 1 , R 2 , R 3 , R 4 and n is the same as above.

[0061] The organosilicon compound represented by the formula (1) may be the same as those exemplified above, and the amount used may be the same as above.

[0062] The silica particles used in the present invention may be further surface-modified with one or more silane compounds represented by the following formula (5) and / or the following formula (6): 5 3SiY (5) R 5 3Si-NH-SiR 5 3 (6) (wherein, R 5 and Y are the same as above.

[0063] The compounds represented by the formulas (5) and (6) include the same compounds as those exemplified above, and the amounts used are also the same as those mentioned above.

[0064] Furthermore, in order to promote the reaction of the organosilicon compound and, optionally, the silane compound with the silica surface, the hydrophilic spherical silica particle dispersion used in step (β) preferably contains a basic substance. Examples of basic substances include those exemplified in step (α), preferably ammonia and diethylamine, and particularly preferably ammonia. The use of ammonia improves the surface treatment efficiency and is effective in simplifying the purification process because it can be removed by distillation. When a basic substance is used, the amount used is preferably 1 to 5 moles, more preferably 2 to 3 moles, per mole of hydrolyzable group in the compound represented by formula (1), optionally (5) and / or (6).

[0065] The conditions for the hydrolysis condensation reaction (surface treatment) in step (β) can be the same as those for step (α). For example, the reaction is preferably carried out at a reaction temperature of 20 to 120°C for a reaction time of 1 to 8 hours, and more preferably at a reaction temperature of 20 to 100°C for a reaction time of 1 to 6 hours.

[0066] Step (γ): Dispersion medium replacement step This step is, if necessary, to the dispersion liquid of silica particles that have been surface-treated with organosilicon compounds obtained in step (β), add the bifunctional (meth)acrylate of component (B) and / or the trifunctional (meth)acrylate of component (C) described below, and remove the hydrophilic organic solvent, water, and the alcohol that may be generated by condensation by distillation.At this time, the bifunctional (meth)acrylate of (B) and / or the trifunctional (meth)acrylate of (C) can be added to the dispersion liquid in advance, or can be added to the dispersion liquid after the alcohol etc. starts to be distilled off, but it is preferable to add it to the dispersion liquid in advance and then distill off.By this step, obtain the silica dispersion liquid in which the silica particles that have been surface-treated with organosilicon compounds are dispersed in the bifunctional (meth)acrylate of (B) and / or the trifunctional (meth)acrylate of (C).

[0067] Methods for distilling off the hydrophilic organic solvent, water, and volatile by-products such as alcohol produced by condensation include distillation at atmospheric pressure and distillation under reduced pressure, with distillation under reduced pressure being preferred. When heating is performed during distillation under reduced pressure, the temperature is preferably 30 to 100°C, more preferably 40 to 80°C, and even more preferably 50 to 70°C. Heating to 30°C or higher is preferred because it can shorten the time required for solvent distillation, while heating to 100°C or lower is preferred because it can suppress side reactions such as thermal polymerization of the acrylic compound and transesterification of the solvent and the acrylic moiety, and may improve the scratch resistance of the cured film obtained when the composition is added to a photocurable composition.

[0068] The amount of bifunctional (meth)acrylate and / or trifunctional (meth)acrylate added is not particularly limited, but in the silica dispersion obtained by step (γ), the surface-treated silica particles are preferably dispersed in an amount of 5 to 250 parts by weight, more preferably 10 to 200 parts by weight, even more preferably 25 to 150 parts by weight, and most preferably 50 to 125 parts by weight, per 100 parts by weight of the (B) bifunctional (meth)acrylate and / or (C) trifunctional (meth)acrylate. Dispersing 5 parts by weight or more of silica improves the scratch resistance of the resulting cured film when added to a photocurable composition, while dispersing 250 parts by weight or less improves the fluidity of the dispersion. Additives such as base neutralizers, acid neutralizers, base adsorbents, acid adsorbents, polymerization inhibitors, antioxidants, UV absorbers, and light stabilizers can be blended into the silica dispersion obtained in this manner to enhance its storage stability, provided that the effects of the present invention are not impaired.

[0069] <(B) Difunctional (meth)acrylate> The component (B) is a difunctional (meth)acrylate. Examples of the bifunctional (meth)acrylate of the component (B) include dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate (HDDA), tetraethylene glycol diacrylate, neopentyl glycol diacrylate, 3-methyl-1,5 pentanediol diacrylate, 1,9-nonanediol diacrylate, dimethylol-tricyclodecane diacrylate, hydroxypivalic acid neopentyl glycol acrylic acid adduct, 2-hydroxy-3-acryloyloxypropyl methacrylate, ethylene glycol diacrylate, polyethylene glycol (n=2 to 15) diacrylate, polypropylene glycol (n=2 to 15) diacrylate, polybutylene glycol (n=2 to 15) diacrylate, and trimethylolpropane diacrylate. These compounds may be used alone or in combination of two or more. Among these, from the viewpoints of curability and low viscosity, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate (HDDA), tetraethylene glycol diacrylate, neopentyl glycol diacrylate, 3-methyl-1,5 pentanediol diacrylate, and 1,9-nonanediol diacrylate are particularly preferred.

[0070] The amount of the bifunctional (meth)acrylate compound (B) is preferably 10% by mass or more, more preferably 10 to 45% by mass, and even more preferably 20 to 45% by mass, based on the total amount of the photocurable composition. A bifunctional (meth)acrylate compound content of 10% by mass or more is preferred because thickening of the composition can be prevented, while a bifunctional (meth)acrylate compound content of 45% by mass or less is preferred because photocurability and scratch resistance are improved.

[0071] <(C) Trifunctional (meth)acrylate> The component (C) is a trifunctional (meth)acrylate. Examples of the trifunctional (meth)acrylate of the component (C) include trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy triacrylate, glycerin propoxy triacrylate, tris(2-acryloxyethyl)isocyanurate, and pentaerythritol triacrylate. These may be used alone or in combination of two or more. Of these, trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy triacrylate, and glycerin propoxy triacrylate are particularly preferred from the viewpoints of curability and low viscosity.

[0072] The amount of component (C) is preferably 5% by mass or more, more preferably 5 to 75% by mass, and even more preferably 9 to 70% by mass, based on the total amount of the photocurable composition. When the content of the trifunctional (meth)acrylate compound is 5% by mass or more, photocurability and abrasion resistance are improved, which is preferable, and when the content of the trifunctional (meth)acrylate compound is 75% by mass or less, thickening of the composition can be prevented, which is preferable.

[0073] The total amount of components (A), (B), and (C) is 70% by mass or more, preferably 70 to 98% by mass, and more preferably 80 to 95% by mass, based on the total mass of the composition. If the amount is less than 70% by mass, photocurability and abrasion resistance will be insufficient.

[0074] <(D) Photoradical Initiator> The component (D) is a photoradical initiator. Specific examples of the photoradical initiator for the component (D) include acetophenone, propiophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one (OMNIRAD 651, manufactured by IGM Resin's), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (OMNIRAD 1173, manufactured by IGM Resin's), 1-hydroxy-cyclohexyl-phenyl-ketone (OMNIRAD 184, manufactured by IGM Resin's), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (OMNIRAD 2959, manufactured by IGM Resin's), and the like. IGM RESINS), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (OMNIRAD 127: IGM RESINS), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (OMNIRAD 907: IGM RESINS), 2-benzyl-2-dimethylamino-(4-morpholinophenyl)-butanone-1 (OMNIRAD 369: IGM RESINS), 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (OMNIRAD 379: IGM RESINS), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (OMNIRAD TPO-H: manufactured by IGM RESINS), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (OMNIRAD 819: manufactured by IGM RESINS); 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)] (IRGACURE OXE 01: manufactured by BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) (IRGACURE OXE 02: manufactured by BASF);Examples of such an oxyphenylacetic acid include a mixture of 2-[2-oxo-2-phenylacetoxyethoxy]ethyl ester and 2-(2-hydroxyethoxy)ethyl ester of oxyphenylacetic acid (OMNIRAD 754, manufactured by IGM RESINS), phenylglyoxylic acid methyl ester (OMNIRAD MBF, manufactured by IGM RESINS), ethyl 4-dimethylaminobenzoate (DAROCUR EDB, manufactured by IGM RESINS), 2-ethylhexyl 4-dimethylaminobenzoate, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, benzoyl peroxide, and cumene peroxide. These may be used alone or in combination of two or more.

[0075] The component (D) preferably contains both an alkylphenone compound and an acylphosphine oxide compound, in order to improve photocurability and abrasion resistance. Examples of suitable compounds include 2-hydroxy-2-methyl-1-phenyl-propan-1-one (OMNIRAD 1173, manufactured by IGM RESINS), 1-hydroxy-cyclohexyl-phenyl-ketone (OMNIRAD 184, manufactured by IGM RESINS), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (OMNIRAD 2959, manufactured by IGM RESINS), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (OMNIRAD 127, manufactured by IGM RESINS). an alkylphenone compound selected from the group consisting of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (OMNIRAD 907, manufactured by IGM RESINS), 2-benzyl-2-dimethylamino-(4-morpholinophenyl)-butanone-1 (OMNIRAD 369, manufactured by IGM RESINS), and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (OMNIRAD 379, manufactured by IGM RESINS), and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (OMNIRAD TPO-H, manufactured by IGM RESINS), It is more preferable that the composition contains in combination an acylphosphine oxide compound selected from the group consisting of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (OMNIRAD 819: manufactured by IGM RESINS), and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (OMNIRAD 819: manufactured by IGM RESINS).

[0076] The amount of component (D) is preferably 2 to 15% by mass, more preferably 5 to 10% by mass, based on the total amount of the photocurable composition. A photoradical initiator content of 2% by mass or more is preferred because it improves photocurability and abrasion resistance, while a photoradical initiator content of 15% by mass or less is preferred because it prevents yellowing and a decrease in abrasion resistance.

[0077] <(E) Other (meth)acrylates> The photocurable composition of the present invention may contain, in addition to the (B) difunctional (meth)acrylate and (C) trifunctional (meth)acrylate, a monofunctional (meth)acrylate or a tetrafunctional or higher polyfunctional (meth)acrylate, as long as the effects of the present invention are not impaired.

[0078] Examples of monofunctional (meth)acrylates include ethyl acrylate, butyl acrylate, ethylhexyl acrylate, 2-hydroxyethyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, etc. Examples of polyfunctional (meth)acrylates include pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate (acrylate product of an adduct of dipentaerythritol and ε-caprolactone), caprolactone-modified dipentaerythritol hydroxypentaacrylate, ditrimethylolpropane tetraacrylate, N-vinylpyrrolidone, aliphatic urethane acrylate oligomers, and aliphatic polyester acrylate oligomers. Among these, ethoxylated pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate (DPHA) are preferred.

[0079] When a tetrafunctional or higher polyfunctional (meth)acrylate is blended, the blending amount is preferably less than 20 mass% based on the total mass of the photocurable composition, because this not only prevents the composition from thickening but also improves the photocurability and abrasion resistance.

[0080] <(F) Ultraviolet Absorber> The photocurable composition of the present invention may contain an ultraviolet absorber within a range that does not impair the effects of the present invention. Examples of the ultraviolet absorber include benzotriazole-based, triazine-based, benzophenone-based, and benzoate-based ultraviolet absorbers. Specific examples include 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole (RUVA-93; manufactured by Otsuka Chemical Co., Ltd.), 2,4-dihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2',4,4'-tetrahydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.), 2,2'-dimethoxy-4,4'-dimethoxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.), and Tinuvin 405 (manufactured by BASF; 2-[4-[(2-hydroxy) Examples of such ultraviolet absorbers include 2-[4-{(hydroxy-3-(2'-ethyl)hexyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine), Tinuvin 400 (manufactured by BASF; 2-[4-{(hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine), Tinuvin 479 (manufactured by BASF; 2-[2-hydroxy-4-(1-octyloxycarbonylethoxy)phenyl]-4,6-bis(4-phenylphenyl)-1,3,5-triazine), and ultraviolet absorbers described in Japanese Patent Nos. 6,156,214 and 6,354,665. These ultraviolet absorbers may be used alone or in combination of two or more. Among these, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-[2-hydroxy-4-(1-octyloxycarbonylethoxy)phenyl]-4,6-bis(4-phenylphenyl)-1,3,5-triazine, and the ultraviolet absorbers described in Japanese Patent No. 6354665 are preferred.

[0081] When an ultraviolet absorber is used, the blending amount is preferably 1 to 15% by mass, more preferably 5 to 10% by mass, based on the photocurable composition. A content of 1% by mass or more of the ultraviolet absorber is preferred because weather resistance is improved, while a content of 15% by mass or less is preferred because yellowing, poor curing, and reduced abrasion resistance can be prevented.

[0082] <Other Additives> The photocurable composition of the present invention may contain additives such as a polymerization inhibitor, an antioxidant, a light stabilizer, and a leveling agent, as long as the effects of the present invention are not impaired.

[0083] Examples of polymerization inhibitors include hydroquinone, p-methoxyphenol, t-butylcatechol, phenothiazine, benzofuroxan, nitrosobenzene, 2-methyl-2-nitrosopropane dimer, N-t-butyl-α-phenylnitrone, etc. When a polymerization inhibitor is used, the amount blended is about 100 to 10,000 ppm based on the mass of the organosilicon compound having a (meth)acrylic group used in the composition.

[0084] Examples of the antioxidant include hindered amine antioxidants and hindered phenol antioxidants. Examples of the hindered amine antioxidant include N,N',N'',N'''-tetrakis-(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine, and dibutylamine / 1,3,5-triazine / N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine / N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine. polycondensation polymer of poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, [decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidyl)ester, 1,1-dimethyl Reaction products of diethyl hydroperoxide and octane (70% by mass)]-polypropylene (30% by mass), bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 1-[ Examples of the hydroxyphenyl ester include, but are not limited to, 2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, and 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione.

[0085] Examples of hindered phenol-based antioxidants include pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis[3-(3,5-di- tert-butyl-4-hydroxyphenylpropioamide)], benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy C7-C9 side chain alkyl ester, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3',3'',5,5',5''-hexane-tert-butyl-4-a,a',a''- (Mesitylene-2,4,6-tolyl)tri-p-cresol, calcium diethyl bis[[[3,5-bis-(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate], 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl Examples of antioxidants include, but are not limited to, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, a reaction product of N-phenylbenzenamine and 2,4,4-trimethylpentene, and 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol. The antioxidants may be used alone or in combination of two or more.

[0086] Examples of light stabilizers include benzotriazole-based, hindered amine-based, and benzoate-based compounds. Hindered amine-based light stabilizers are preferred. Among these, tertiary amine-containing hindered amine-based light stabilizers are preferred for improving the storage stability of the composition. Examples of tertiary amine-containing hindered amine-based light stabilizers include TINUVIN 622LD, TINUVIN 144, TINUVIN 123, and CHIMASSORB 119FL (all manufactured by BASF); MARKLA-57, LA-62, LA-67, and LA-63 (all manufactured by Asahi Denka Co., Ltd.); and SANOL LS-765, LS-292, LS-2626, LS-1114, and LS-744 (all manufactured by Sankyo Co., Ltd.).

[0087] Examples of the leveling agent include "KP-341" manufactured by Shin-Etsu Chemical Co., Ltd., "BYK-180" and "BYK-190" manufactured by BYK Chemie, and "LE-604" manufactured by Kyoeisha Chemical Co., Ltd.

[0088] In addition to the above-mentioned additives, the photocurable composition of the present invention may also contain, if necessary, silicone resins, pigments, dyes, metal powders, heat ray reflecting / absorbing agents, flexibility imparting agents, antistatic agents, antifouling agents, water repellency imparting agents, and the like.

[0089] In the photocurable composition of the present invention, the content of the volatile organic solvent relative to the entire composition is preferably less than 10% by mass, more preferably less than 5% by mass, and particularly preferably less than 1% by mass, in order to reduce the burden on the environment. Note that the solvent also includes components that are not intentionally added to the composition, such as reaction solvents that could not be completely removed by distillation under reduced pressure and alcohols generated by hydrolysis of alkoxysilyl groups.

[0090] The photocurable composition of the present invention has a kinematic viscosity of 100 mm at 25°C. 2 / s or less is preferable, and 75 mm 2 / s or less is more preferable, and 50 mm 2 The kinematic viscosity at 25°C is preferably 100 mm / s or less. 2When the kinematic viscosity is 1 / s or less, the coating workability is improved and in addition, it is possible to use a coating method suitable for coating a low viscosity liquid, such as flow coating or spray coating, which is particularly preferable. 2 / s) can be measured using a Cannon-Fenske viscometer (manufactured by Shibata Corporation) or the like.

[0091] [Cured Product] The photocurable composition of the present invention can be cured by irradiating it with ultraviolet light in an atmosphere such as air or nitrogen. Examples of lamps with a wavelength range within the reactive range include a high-pressure mercury lamp (UV-7000) and metal halide lamps (MHL-250, MHL-450, MHL-150, MHL-70) manufactured by Ushio Inc., a metal halide lamp (JM-MTL2KW) manufactured by JMtech, an ultraviolet irradiation lamp (OSBL360) manufactured by Mitsubishi Electric Corporation, an ultraviolet irradiator (UD-20-2) manufactured by Japan Storage Battery Co., Ltd., a fluorescent lamp (FL-20BLB) manufactured by Toshiba Corporation, and an H bulb, H plus bulb, D bulb, Q bulb, or M bulb manufactured by Fusion Electronics. The irradiation dose is 100 to 12,000 mJ / cm. 2 is preferred, and more preferably 300 to 8,000 mJ / cm 2 and more preferably 500 to 6,000 mJ / cm 2 It has been confirmed that the composition of the present invention tends to have particularly good abrasion resistance when cured by ultraviolet light irradiation in an atmospheric environment. Therefore, it is preferable to irradiate the composition of the present invention with ultraviolet light in an atmospheric environment.

[0092] [Coated Article] The photocurable composition of the present invention can be applied to at least one surface of a substrate, either directly or via at least one other layer, and then cured by the above-mentioned light irradiation to form a coating, thereby obtaining a coated article.

[0093] The substrate is not particularly limited, but examples thereof include plastic molded bodies, wood-based products, ceramics, glass, metals, and composites thereof. Furthermore, substrates whose surfaces have been treated, specifically, substrates treated with chemical conversion coating, corona discharge treatment, plasma treatment, acid or alkali solution, etc., and decorative plywood in which the substrate body and the surface layer are coated with different types of paint can also be used. In particular, when a cured film made of the photocurable composition of the present invention is formed on a polycarbonate substrate, it is possible to improve the abrasion resistance and weather resistance of the polycarbonate.

[0094] Alternatively, the photocurable composition of the present invention may be applied to a substrate surface on which other functional layers have already been formed, such as a primer layer, an anticorrosive layer, a gas barrier layer, a waterproof layer, and a heat-shielding layer, and one or more of these layers may be formed in advance on the substrate.

[0095] The coated article may be further coated on the surface on which the cured film made of the composition is formed with one or more layers such as a vapor-deposited layer formed by chemical vapor deposition (CVD), a hard coat layer, an anticorrosive layer, a gas barrier layer, a waterproof layer, a heat-shielding layer, an antifouling layer, a photocatalytic layer, an antistatic layer, etc. Furthermore, the coated article may be further coated on the surface opposite to the surface on which the cured film made of the composition is formed with one or more layers such as a hard coat layer, an anticorrosive layer, a gas barrier layer, a waterproof layer, a heat-shielding layer, an antifouling layer, a photocatalytic layer, an antistatic layer, etc.

[0096] The method for applying the photocurable composition of the present invention may be appropriately selected from known techniques, and various application methods such as brush coating, spraying, dipping, flow coating, roll coating, curtain coating, spin coating, and knife coating can be used.

[0097] The thickness of the cured film in the coated article of the present invention is not particularly limited and may be appropriately selected depending on the intended use, but is preferably 0.1 to 50 μm, and particularly preferably 1 to 20 μm in order to satisfy the requirements for hardness, abrasion resistance, long-term stable adhesion, and absence of cracks in the cured film. The film thickness can be appropriately adjusted by the amount of coating, etc.

[0098] One of the characteristics of the coated article of the present invention is the visible light transmittance of the cured film. Visible light transmittance is generally evaluated by the cloudiness (haze %) of the cured film, with the smaller the haze, the better the visible light transmittance. The haze can be measured using a turbidity meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The haze of a cured film generally increases with film thickness. In the coated article of the present invention, when the cured film has a film thickness of 5 μm or less, the haze is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.0 or less.

[0099] One of the features of the coated article of the present invention is the excellent abrasion resistance of the cured film. Abrasion resistance is measured in a Taber abrasion test according to ASTM 1044, using an SC-10F abrasion wheel, and measuring the haze after 500 revolutions under a load of 500 gf. The difference in haze (ΔHz, % points) before and after the test is compared; the smaller the ΔHz, the better the abrasion resistance. In the coated article of the present invention, ΔHz is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less.

[0100] The present invention will be specifically explained below by showing synthesis examples, examples and comparative examples, but the following examples do not limit the present invention in any way.

[0101] [1] Preparation of Surface-Modified Silica Dispersion [Synthesis Example 1] Step (α): 396 g of methanol, 16 g of water, and 20 g of 28% by weight aqueous ammonia were added to a 1-liter glass reactor equipped with a stirrer, a dropping funnel, and a thermometer, and mixed. The solution was adjusted to 50°C, and 323 g of tetramethoxysilane and 81 g of 5.5% by weight aqueous ammonia were simultaneously added dropwise while stirring. After the dropwise addition was completed, stirring was continued at 50°C for 1 hour to carry out hydrolysis, yielding a sol-gel silica particle dispersion. The nonvolatile component content of the resulting dispersion (105°C, 3 hours) was 18% by weight.

[0102] Step (β): To 837 g of the sol-gel silica particle dispersion obtained in the above step (α), 22.6 g of 3-methacryloxypropyltrimethoxysilane was added at 25° C., and stirring was continued for 2 hours. Thereafter, 15.1 g of trimethylsilanol (LS-310: manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and stirring was continued for 1 hour to obtain a water-methanol dispersion of surface-modified silica particles (A-1).

[0103] Step (γ): To the water-methanol dispersion of the surface-modified silica particles (A-1) obtained in step (β) above, 1,6-hexanediol diacrylate (HDDA: manufactured by Daicel Corporation, component B-1) was added at 25°C in an amount equal to the mass of the silica particles, and then low-boiling point components in the dispersion were distilled off at 50°C under reduced pressure (6,650 Pa) to obtain a 50 mass% HDDA (B-1) dispersion of the surface-modified silica particles (A-1).

[0104] Synthesis Example 2 A 50 mass % dispersion of surface-modified silica particles (A-2) in HDDA (B-1) was obtained in the same manner as in Synthesis Example 1, except that in step (β) of Synthesis Example 1, 3-methacryloxypropyltrimethoxysilane was changed to 27.5 g of 8-methacryloxyoctyltrimethoxysilane (KBM-5803: manufactured by Shin-Etsu Chemical Co., Ltd.).

[0105] Synthesis Example 3 A 50 mass % dispersion of surface-modified silica particles (A-3) in HDDA (B-1) was obtained in the same manner as in Synthesis Example 1, except that in step (β) of Synthesis Example 1, 3-methacryloxypropyltrimethoxysilane was changed to 20.0 g of methacryloxymethyltrimethoxysilane (manufactured by Gelest).

[0106] [2] Evaluation of Physical Properties of Surface-Modified Silica Particles The following measurements were carried out on the surface-modified silica particles (A-1) to (A-3) obtained in the above Synthesis Examples 1 to 3. The results are shown in Table 1.

[0107] [Particle size] The dispersion was diluted with methanol so that the concentration of surface-modified silica particles became 1% by mass, and after irradiating with ultrasound for 10 minutes, the particle size distribution was measured using a dynamic light scattering / laser Doppler method Nanotrac particle size distribution analyzer (UPA-EX150, manufactured by Nikkiso Co., Ltd.), and the volume-based median diameter (D50) and D90 / D10 value were calculated.

[0108] [Q 4 / Q] under the following conditions 29 In the spectrum obtained by Si-NMR measurement, the peak area (Q) from −105 to −130 ppm relative to the peak area (Q) from −80 to −130 ppm 4 ) ratio (Q 4 / Q) was calculated. Apparatus: Pulse-Fourier transform nuclear magnetic resonance spectrometer (JNM-ECX500II: manufactured by JEOL Ltd.) Magnetic field strength: 11.75 T Number of accumulations: 10640 S / N ratio: >5 Sample tube material: Polytetrafluoroethylene Solvent: Deuterated chloroform Reference substance: Tetramethylsilane Relaxant: Chromium (III) acetylacetonate

[0109] [Content of Organosilicon Compound] The content of the organosilicon compound having a (meth)acrylic group was calculated by {[Amount of organosilicon compound having a (meth)acrylic group added] / [Mass of sol-gel silica before surface modification]}×100 (mass%).

[0110]

[0111] [3] Preparation of Photocurable Compositions [Examples 1-1 to 1-15, Comparative Examples 1-1 to 1-7] Photocurable compositions were prepared by mixing the 50 mass % HDDA (B-1) dispersions of the surface-modified silicas (A-1) to (A-3) obtained in Synthesis Examples 1 to 3 and the following components in the blending ratios (mass %) shown in Tables 2 and 4.

[0112] (C) Component: Trifunctional (meth)acrylate (C-1) Trimethylolpropane ethoxy-modified triacrylate (Miramer M3130: manufactured by MIWON Co., Ltd.) (C-2) Trimethylolpropane triacrylate (Miramer M300: manufactured by MIWON Co., Ltd.)

[0113] Component (D): Photoradical initiator (D-1) 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad 1173: manufactured by IGM RESINS B.V.) (D-2) 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (Omnirad TPO-H: manufactured by IGM RESINS B.V.)

[0114] (E) Component: tetrafunctional or higher polyfunctional (meth)acrylate (E-1) Ethoxylated pentaerythritol tetraacrylate (Miramer M4004: manufactured by MIWON Co., Ltd.) (E-2) Dipentaerythritol hexaacrylate (Miramer M600: manufactured by MIWON Co., Ltd.)

[0115] Component (F): UV absorber (F-1) 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole (RUVA-93: manufactured by Otsuka Chemical Co., Ltd.) (F-2) Hydroxyphenyltriazine-based UV absorber (Tinuvin 479: manufactured by BASF Japan Ltd.) (F-3) UV absorber represented by the following structural formula, produced according to Synthesis Example 1 of Japanese Patent No. 6354665

[0116]

[0117] [4] Evaluation of physical properties of photocurable compositions The photocurable compositions obtained in Examples 1-1 to 1-15 and Comparative Examples 1-1 to 1-7 were evaluated as follows. The results are shown in Tables 2 and 4.

[0118] [Kinematic Viscosity] The kinematic viscosity of the composition at 25°C was measured using a Cannon-Fenske viscometer (manufactured by Shibata Corporation).

[0119] [5] Production of cured films and coated articles [Examples 2-1 to 2-15, Comparative Examples 2-1 to 2-7] The compositions obtained in Examples 1-1 to 1-15 and Comparative Examples 1-1 to 1-7 were applied to a polycarbonate plate (5 mm thick, product name: Takiron PC Clear 1600 type, manufactured by Takiron C.I. Co., Ltd.) using a bar coater #8, and then exposed to 1800 mJ / cm in the air using a high-pressure mercury lamp. 2(ultraviolet integrated energy of wavelength 300 to 390 nm, measured with an Eye ultraviolet integrated illuminance meter UVPF-A1 (PD-365): manufactured by Iwasaki Electric Co., Ltd.) to prepare a cured film having a thickness of 10 μm.

[0120] [6] Evaluation of physical properties of cured film The polycarbonate plates having the cured films formed thereon were evaluated for transparency and abrasion resistance as described below. The results are shown in Tables 3 and 5.

[0121] [Transparency] Haze (%) was measured using a turbidity meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0122] [Abrasion Resistance] In accordance with ASTM 1044, an abrasion wheel SC-10F was attached in a Taber abrasion test, and the haze after 500 rotations under a load of 500 gf was measured using a haze meter (NDH5000SP, manufactured by Nippon Denshoku Industries Co., Ltd.), and the difference (ΔHz, % points) from the value before the abrasion test was calculated.

[0123]

[0124]

[0125]

[0126] *Measurement is not possible due to cloudiness of the coating

[0127] As shown in Table 2, the photocurable compositions of Examples 1-1 to 1-15, which satisfied the requirements of the present invention, had low viscosity, and as shown in Table 3, the cured films exhibited excellent transparency and abrasion resistance. On the other hand, as shown in Table 5, Comparative Examples 2-1 and 2-2, which did not contain inorganic particles, exhibited significantly poor abrasion resistance. Comparative Example 2-3, which did not contain (C) trifunctional (meth)acrylate, exhibited cloudy coatings and significantly impaired transparency. Furthermore, Comparative Examples 1-4 to 1-6, in which the trifunctional (meth)acrylate (C) in the composition of Example 1-1 was replaced with a tetrafunctional or higher polyfunctional (meth)acrylate, exhibited high viscosity compositions. In Comparative Examples 2-4 to 2-6, the abrasion resistance deteriorated as the content of dipentaerythritol hexaacrylate increased. Additionally, when component (A) was in excess, as in Comparative Example 1-7, the composition exhibited high viscosity, and Comparative Example 2-7 also exhibited poor transparency.

Claims

1. (A) surface-modified inorganic particles in which at least one of an organosilicon compound represented by the following formula (1), a hydrolyzate thereof, and a condensate thereof is chemically bonded in an amount of 1 to 30 parts by mass per 100 parts by mass of inorganic particles, and the median diameter in a volume-based particle size distribution is 1 to 60 nm; (B) a difunctional (meth)acrylate, (C) a trifunctional (meth)acrylate, and (D) Photoradical initiator Including, The photocurable composition according to claim 1, wherein the blending amount of the component (A) is 10 to 35% by mass, and the combined blending amount of the components (A), (B) and (C) is 70% by mass or more. 【Chemistry 1】 (In the formula, R 1 is a hydrogen atom or a methyl group, R 2 is an alkylene group having 1 to 20 carbon atoms, R 3 are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; R 4 are each independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, and n is an integer of 1 to 3.

2. 2. The photocurable composition according to claim 1, wherein the inorganic particles are silica particles.

3. 3. The photocurable composition according to claim 2, wherein the surface-modified inorganic particles have a D90 / D10 value in a volume-based particle size distribution of 3.2 or less.

4. The surface-modified inorganic particles are 29 The peak area (Q) from -80 to -130 ppm in the Si-NMR spectrum is 4 ) ratio (Q 4 3. The photocurable composition according to claim 2, wherein the sol-gel silica particles having a surface-modified ratio of 0.8 to 1.

0.

5. The photocurable composition according to claim 1, wherein the surface-modified inorganic particles further have at least one selected from the group consisting of a silane compound represented by the following formula (5) and a disilazane compound represented by the following formula (6) chemically bonded thereto: R 5 3 SiY (5) R 5 3 Si-NH-SiR 5 3 (6) (In the formula, R 5 are each independently an alkyl group having 1 to 8 carbon atoms, and each Y is independently a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 6 carbon atoms, an amino group, or a halogen atom.

6. 2. The photocurable composition according to claim 1, wherein the content of the volatile organic solvent is less than 10% by mass based on the entire composition.

7. The kinetic viscosity at 25°C is 100 mm 2 The photocurable composition according to claim 1, wherein the viscosity is 1 / s or less.

8. A cured product obtained by curing the photocurable composition according to any one of claims 1 to 7.

9. An article coated with the cured product according to claim 8.

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